“And by the end we were sort of slurring our words. You can get drunk without drinking alcohol, it turns out.”

‘New audience for live theatre’

The play sees a reunion for the two stars of the X-Men movies and both actors believe fans of their other major screen franchises will also visit the theatre.

Sir Ian played Gandalf in the Lord of the Rings and Hobbit movies, while Sir Patrick was Captain Jean-Luc Picard in Star Trek: The Next Generation.

Sir Patrick said: “It gives both of us a lot of satisfaction that, because of the very popular and successful franchises we’ve been in, we are creating a new audience for live theatre, and especially a young audience.

“Teenagers who have been watching The Hobbit and The Lord of the Rings – they want to see Gandalf, they want to see Jean Luc Picard and Charles Xavier and Magneto.

“That doesn’t matter to us. We don’t care why they come.”

Front Row is on BBC Radio 4 on 3 August at 19:15 BST – the episode will later be available on the Front Row website.